96 XP - DESS changed behavior. Suddenly, have to press Start before it sees the key.

[redwing57]

First post here, glad this forum exists.

I have a 96 XP that's worked fine for the 12 years I've owned it. Always just put the DESS lanyard key on the post, beep-beep, hit start. Always. Boat runs great.

This weekend, I started it on the trailer for a few seconds in preparation for launching. Then went to launch it. At the launch, the boat suddenly doesn't react to the lanyard, the DESS key. Nothing. No wakeup, nothing.

But, I stumbled upon a new behavior. If I press the Start button, wake up the electronics first, then it sees the DESS key, starts, runs, no issues. It's consistent, every time, this sequence works.

I checked out the DESS post connections with a multimeter, all works normally. I pulled the MPEM housing open, all fuses are fine, all connections look clean and solid. Nothing I can find seems out of the ordinary. Ran through the advanced diagnostics mode, no error codes. And, the boat seems to run normally after the lanyard's attached.

But a sudden behavior change in a system makes me a little nervous. Has anyone run into this before? Why would it suddenly not recognize the lanyard's on the DESS post unless the electronics are awake? Is it a problem, or do you suppose I can just live with it?

Thanks in advance for any help or advice anyone may provide.

 

[Coastiejoe]

Well,,, some of the newer skis, (not all of them) require you to "wake the ski up" first. If you do not do so, then it will not see the DESS even with the lanyard replaced.

You are describing perfectly normal behavior for about 50% of the skis out there. That said,,, if it was never like this before, I can see why you would have a concern.

You are in the "if it's not broke you can't fix it mode" right now...

 

[1983]

Clean the DESS post on the ski, the metal ring, and the center metal dot in middle.

Then clean the key contacts. This can help alot. I spray contact cleaner for clean electrical connections in mine once in a while cause they get wet, and sometimes get a little dirty.

I would leave ski alone like Joe said, other than cleaning the contacts.



Rob

 

[redwing57]

Ok, an update. I found the issue. It's actually a partially-bad DESS post!

When it's dry, like after sitting on the trailer a few days, it works normally. But at the launch, when it gets wet, it quits working.

I checked it out with an ohmmeter. When it's gotten wet, instead of the open circuit it's supposed to have without the key attached, it has about 1000 ohms resistance, not quite closed but nearly so. I think the computer didn't see the transition from open to closed that it expected. It went from 1000 ohms to zero, and it may see 1000 ohms as nearly zero too. This was confirmed by disconnecting the DESS connector (makes an open circuit), put the key on the post, then attached the connector. It did the chirp-chirp as expected. But with the connector together, attaching the key didn't do anything. So, confirmed the issue.

So, I'm replacing the DESS post. I'll update when I get it replaced.

 

[Coastiejoe]

Please do,,,

 

[redwing57]

Ok, so here's the wrap up, the punchline, the denouement of all my efforts.

It's totaled. So, here's what happened.
1) Replaced DESS post, fixed it fine, the new post worked as normal.
2) Replaced the "rectifier" in the engine computer box. System voltage now stable at 14 V at all rpms.
3) Replaced the fuel sender. Now reads quite properly, as before.

So, it's back to the baseline we had at the end of last season, where on occasion it would bog under acceleration. It dies with open throttle, like a fuel issue. Drat! I give up, take it to a pro.

Pro calls me, says there are leaking gaskets allowing air in after the carbs. Also, one cylinder 5 psi low pressure, so likely scuffed piston or some such. Bottom line, $200 to tear down for full examination, likely $1000-3000 to overhaul.

The thing's only worth $1000-1500 in running order, and I was really just wanting to get it running so I could sell it anyway.

Therefore, it's totaled since it will cost more to repair than it's worth. I'm done. Done, done, done. Selling it to the pro for scrap value.

Any suggestions for a 3 place that has performance like the 96 XP?

 

[mikidymac]

Hold on a minute!!

A 5 psi difference between cylinders is no cause for alarm. Rule of thumb would be 10% is an issue so at 150psi standard compression that is 15psi difference. What is the actual compression on each cylinder?

If and air leak after the carbs is your actual issue there are only 2 places. The carb gaskets at $5 each and the rotary cover o-ring at $10. So what $20 in parts to fix your ski?

Also where does he get $1000-$3000 to overhaul? A fresh engine with 2 year no fault warranty is only $1,000.

 

[redwing57]

Hold on a minute!!

A 5 psi difference between cylinders is no cause for alarm. Rule of thumb would be 10% is an issue so at 150psi standard compression that is 15psi difference. What is the actual compression on each cylinder?

If and air leak after the carbs is your actual issue there are only 2 places. The carb gaskets at $5 each and the rotary cover o-ring at $10. So what $20 in parts to fix your ski?

Also where does he get $1000-$3000 to overhaul? A fresh engine with 2 year no fault warranty is only $1,000.

Hmm. I looked at a rebuilt engine, but even at $1000-$1300 (installation) I'm just not interested.

Do you have to pull the engine to change the carb gaskets? He said something about the engine case too. Is there some gasket system there?

 

[1of500]

Rebuild the carbs install new base gaskets when you reinstall the carbs problem solved

 

[redwing57]

So I called the shop and probed this question a bit.

It's primarily the engine case gasket apparently, item 17 in this exploded view of a similar Rotax engine:
https://cometkartsales.com/images/D/crankcase-bg.jpg

It takes a full engine disassembly to get this apart and replaced. That's the bulk of the work to do a full overhaul. Many bux.

 

[howie099]

So this shop did a block leak down test for you to find this leak? Ususally you need to remove stuff to do a proper leak down test like the carbs and most places wouldn't do that for free. Me I would want to see the leak. That's a 20 year old engine you just swap or rebuild if if that is true. You can swap an engine if you have normal hand tools and can operate them.

 

[mikidymac]

I get the feeling this shop might not be on the up and up. THe link you posted is not even for a watercraft and #17 is the case gasket that these skis don't even have. Without doing a full leakdown test with te engine out I don't think they would find a leak in the cases and I have never personally seen a case leak on these skis. IF it isn't your carb base gaskets leaking the only thing left is the rotary cover o-ring like I said.

 

[hotrodssnova]

Or a cracked oil pump line between oil pump and brass nipple on intake

I would think an air leak would cause a lean condition and Rev the engine high. 5 psi isn't a big deal. Could be their gauge, a leaking original on their adapter, not really a big deal.

 

[1983]

Shop is taking you to the cleaners on that estimate, 110% honest and better help here on forums.


Rob